Association between TNF-α gene 308G>A polymorphism and lung cancer risk: a meta-analysis

Many studies have investigated the association between tumor necrosis factor alpha (TNF-α) gene 308G/A polymorphism and lung cancer risk, but the results were inconsistent. We thus comprehensively searched the PubMed, EMBASE, and BIOSIS Previews databases and extracted data from all eligible articles to estimate the association between TNF-α gene 308G/A polymorphism and lung cancer risk. The pooled odds ratio (OR) with 95 % confidence intervals (CIs) were calculated. Twelve case-control studies in 11 articles involving 2,436 cases and 2,573 controls were included in the meta-analysis to assess the association between TNF-α gene 308G>A polymorphism and susceptibility to lung cancer. Overall, TNF-α gene 308G>A polymorphism was significantly associated with an increased risk of lung cancer for A vs. G (OR = 1.13, 95 % CI 1.00 ~ 1.27, P = 0.04). Subgroup analysis by ethnicity showed that there was a significant association between TNF-α gene 308G>A polymorphism and increased risk of lung cancer in Asians, but not in Caucasians. In subgroup analysis by tumor type, there were significant associations between TNF-α gene 308G>A polymorphism and increased risk of lung cancer in small cell lung cancer (SCLC) for AA+AG vs. GG, in non-small cell lung cancer (NSCLC) for A vs. G, AA vs. GG, and AA+AG vs. GG. No association between the genotypes and different stages of lung cancer was detected. The meta-analysis suggests that TNF-α gene 308G>A polymorphism is associated with an increased risk of lung cancer, particularly among Asians, both for SCLC and NSCLC, considering tumor type.